A potentiometric sensor for studying charge based adsorption of proteins was created using a single‐piece polyaniline‐PVC ion‐selective electrode (ISE). Three different ISEs, two for Na+ and one for Cl− ion determination, were studied. The Na+‐ISEs consisted of a neutral calixarene‐based ionophore and one with a charged carrier dinonylnapthalenesulfonic acid (DNNSA) whereas for the Cl− ISE, an anion exchanger tridodecylmethylammonium chloride (TDDMA+Cl−), was used. The Na+ ISE with DNNSA as the charged carrier was successfully able to discriminate the binding of two different proteins (bovine serum albumin and lysozyme) based on their intrinsic charge.

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We present a model that can be used to compute the charging and potential at any point of the electrochemical system comprising the ion-sensitive floating gate FET (ISFGFET) exposed to an electrolyte solution. In contrast to ion-sensitive FETs, the sensor has an additional control input gate. The model predicts the possibility for electrofluidic gating when the control gate (CG) is used in conjunction with a reference electrode (RE). Electrofluidic gating is the field-effect control over the electric double layer. We consider the applicability of electrofluidic gating in realizable devices and simulate the relationships between oxide properties and electrolyte solution to varying potentials of the CG and the RE. The oxide/electrolyte solution model is merged to the SPICE model of the transistor to create a unified model that can be used to simulate the transfer characteristics of the sensor in absolute terms to change input and electrolyte solution conditions. We simulate the sensor transfer characteristics with common Al 2 O 3 surface to change the pH of the electrolyte solution and compare them to measurements. The results clarify the operation of ISFGFET and its applicability in electrofluidic gating.